The crane requires vertical lifting as the deviation angle of hook shall not exceed 3 degrees when a work-piece is lifted by the mobile crane, but the driver cannot determine whether the hook is in the vertical position for lack of the display on the crane to show vertical hoisting. Especially when collaboratively hoisting, the hoisting commander instructs the drivers to operate and eliminate the load's swing angle with the information from whom monitors the load's angle, and instructs the drivers to operate and make balance of load weight with the information from whom monitors the load's gesture. It is neither timely nor accurate to do that. Here is a system for monitoring the hoisting of cranes, as is shown in FIG. 1. Two vertical measurement devices 4 are fixed to measure the relative vertical gesture between the hoisted object 2 and crane 1, and one horizontal measurement device 3 are fixed to measure the horizontal gesture of the hoisted object 2. The vertical measurement device 4 and horizontal measurement device 3 are respectively connected to measurement monitoring devices 5 via signal chains. The key technologies of the foresaid system are unclear. For example, it is just an assumption that the vertical measurement device 4 is used to measure the relative vertical gesture between the hoisted object 2 and crane 1, and it does not provide a solution of how to install the vertical measurement device 4 on the lifting pulley block; It is unclear to measure the horizontal gesture of the hoisted object 2 by the horizontal measurement device 3, such as how to set the horizontal gesture of boiler if the hoisting object is a boiler, and how to set the horizontal gesture of tower equipment when adopting two cranes to slidingly hoist or three cranes to hoist. Here is a device to dynamically display the hoisting risk in the collaborative crane, which adopts one wireless camera with three switchable channels and one receiver with a display matched with the wireless camera; the display of receiver in the collaborative crane cab displays the load's swing angle and weight which are already displayed in the native crane cab and transmitted by the wireless camera. But this collaborative displaying solution does not apply to the crane without displaying the load's swing angle and weight, especially there is no display set in the crane so far. Therefore, it is just a assumption too. Even if each crane is equipped with a display to show the load's swing angle and weight, it is difficult to get the load's swing angle and weight by the same monitoring device, which seriously affects the comparability between the native crane and the collaborative crane; and the monitoring method is not clear.